Apparatus for washing



March 19, 194() v H. L. ALEXANDER Erm. 2,193,957

APPARATUS Fon wAsHING f4 sheets-sheet 1 FledAug. 31, 1935 INVENTO RSLZexa/de/w* Mardi 19, 1940- H. L. ALEXANDER Er AL 2,193,957

APPARATUS FQR WASHING 4 sheetssheet 2 Filed Aug. 31, 1936 NNW M@ lll l Awww ATTORNEY Avg@ March 19, 1940. H, L. ALEXANDER Er'AL. 2,193,957

APPARATUS Fon WASHING Filed Aug. 31, 193e 4 sheets-sheet 5 LA imlINYENTORS AFPARATUS FOR WASHING Filed Aug. 51, i936 4 sheets-sheet 4ATTORNEY developed and are ofV excellent capacity and perthe partingliquid processare affected by the Patented Mar. 19, 1940 UNITED STATESPATENT OFFICE APPARATUS FOR WASHING Henry L. Alexander, Wilmington,Del., and Willing B. Foulke, Media, Pa., assignors, by mesneassignments, Vto Delaware Chemical Engineering and Development Company,Wilmington, Del., a corporation of Delaware Application August 3?, 1936,Serial No. 98,820

`phenomenon of altered specific gravity but they are distinguished fromfroth flotation. y

The suggestion was made toward the middle of the nineteenth century that4ferrie chloride or sulfuric acid' could be used as a parting liquid forthe separation of coal and slate and attempts were made in England torun the ferrie chloride process in competition with the jigs, butthe'jigs were highly developed, the use of a parting liquid was a baresuggestion and the attempt was a failure because of the undevelopedstate of the Inew process, the highly developed state of jig separation,and the inability of experimenters to make the parting process a successin itself. The original attempt having been made, however, subsequentinventors worked with the suggested process and a host of patents havebeen issued, particularly in England and in the United States,

4 Claims.

This invention relates to the washing of coal and in its broadestapplication to the removal from solids of adhering liquids, particularlyof organic type. y

Coal appears to have been known to, and to some small extent used by,the ancients. Its use inChina at about the year 1200 is described byMarco Polo and about 1500 Agricola described a process of freeingminerals from their gangue which is the direct progenitor of the jigprocess of coal cleaning, which has the widest use today. In the earlydays of coal mining in Europe and in the United States only the thickseams were mined. Hand methods were largely in vogue and the need foranything except hand cleaning, or the most crude of mechanical methodswas unnecessary. As the thick seams were used up, however, it becamenecessary to use thin seams and seams containing veins of rock,'whichentailed the necessity of removing the' rock before the coal could besold. The method which came most prominently into use `and which istoday the standard of separating coal and slate depends upon the ratesat which bodies of different densities sink through a liquid such aswater. It is known that bodies sink through a liquid at rates which arefunctions of their respective densities, the denser sink thel moreswiftly. v The standard jig washer of the industry takes advantage ofthis principle, but instead of permitting the solids to sink through theliquid, the liquid is forced 4 through a screen onv which the solidsrest ata rate which lifts the layer of coal off the heavier slate, thecoal being carried withA the rush of liquid over a weir and the slatebeing discharged 'at a lower point from the screen. lJigs are highly Tothe best of our knowledge and belief, however, the onlyA such processthat has been used successfully is one that depends upon the partingeffect of a suspension of solids such as sand or clay in water. The artwith respect to parting media of homogeneous character is in theindustry today as it was in the nineteenth century, unable to compete.The parting liquids are worth more than the coal and the losses thereofare so great that they outweigh the theoretical advantages of moreaccurate separation. The processes themselves, being crude andundeveloped, are incapablel of competing with the highly developedprocesses already in use in the industry.v They are incomplete,processes, lacking a number of elements essential to success.

It is an object of this invention to separate vcoal from slate,and'other minerals from their formance. However, the competitionof oilhas gangues or from each other, by a process which driven coalproducersto 'find means of cleaning coal which will be more accurate inseparating useful fromA useless lumps and producers and inventors haveturned their thoughts to those processes of separation which depend uponthe parting action of a liquid 'having specific gravity between that ofcoal and that of slate. l provide efficient apparatus for that purpose.

The use of la parting liquid is to be distin-v The objects of theinvention are accomplished, guished from froth flotation.v Frothnotation al- \'generally speaking, by subjecting the separated ters theapparent specific gravity ofa body by materials to vigorous washing withwater while encasingit within a bubble. Parting processes, so actingupon the materials that all portions however, depend upon the use of aparting liquid v"thereof are exposed to4 the effect of the washing inwhich one ingredient of the mixture will sink uid. The objects of theinvention are also acdown and another ingredient of the mixture willrise to and float on the top. Certain phases of intermediatespecicgravity. Another object of the invention is to remove parting liquid ofhalogenated hydrocarbon or other type from the surface of coal or anyother mineral that has been immersed therein or coated therewith, and tometical seal. The objects ofthe invention are to a certain extentaccomplished by the apparatus dealing with vprocesses of the partingliquid type.

depends upon the parting effect of a liquid of complished byI effectingthe washing under her.-

and by the individual details thereof as more fully hereinafterdescribed.

Figure 1 is'an elevational view partly broken away and in sectionshowing the scrubbing apparatus; Figure l-a is a section on the line I-al-a of Figure l; Figure l-b is an enlarged section on the line l-b, l-bof Figure l-d, the left hand section of Figure l-b taken on the line Z-Zof Figure l-d; the middle section of Figure l-b being. taken on the lineY-Y of Figure l-d; and the right hand section of Figure l-b being takenon the line X-X of Figure l-d; Figure l-c is a section on the line l-c,l-c of Figure 1; Figure l-dA is an enlarged section of the sealingmechanism shown in Figure l-c; Figure l-e is an enlarged section of aspray pipe With nozzles showing the overlap of the sprays.

Figure 2 discloses the apparatus for receiving material discharged fromthe scrubbing process, for sealing the scrubbing process, and fordischarging the material.

After the coal has been separated from the indigenous impurities, bothare subjected to a vigorous scrubbing. In order to prevent the loss ofany liquid by evaporation or otherwise the scrubbing is preferablycarried out in a hermetically sealed chamber. A shaker screen is used inorder to make possible the thoroughfwashing of the coal, and the problemof transmitting power to the screen without opening the apparatus to theair was .no small one. It was accomplished, however, by the means whichare more fully described below. Brieiiy stated, the coal is carriedthrough an hermetically sealed connection from the separating apparatusinto the washing section where, constantly tumbled about by a shakerscreen, it is subjected to an extremely vigorous washing whereby toremove all fine particles and substantially all the liquids that havebeen used in the process. The coal and slate are then dropped from thescreen into the water baths of water sealed conveyors. The used liquidis run over a concentrating table, which tends to precipitate suspendedsolids, and to form larger aggregates of suspended liquids, and thewhole runs to the tank which forms the bottom of the machine, where aweir divides the liquids which contain only light suspended solids fromthe heavy sludge. The divisions are respectively drawn oi and treated ina recovery system which will be more com pletely elsewhere described.

In the drawings Figures 1 to l-e are illustrative of this portion of theinvention. In the figures, 4 refers generally to the washing apparatus;40 is a shaker screen; 4l is a coal trough forming part of the saidscreen; 42 is a slate trough forming part of the said screen; 43 is apartition dividing the screen into two sections longitudi-4 nallywhereby to keep the separated coal and slate from becoming intermingled.44 are strips of wood or some similar material which is capable ofwithstanding the abrasive action of the coal and slate; 45 is aforaminous section at the charging end of the screen which permits thedraining of liquid; 46 is a wedge-wire screen which forms the ioor ofthat section of the screen which approaches the discharge end; 41 is asolid bottom to the screen at the discharge; 48 are dischargeI lips.

The construction of the screen is as follows: Angle irons 49 form theside frames of the screen and extend longitudinally from the feedingtroughs to the discharge plate 41. Dividing member 43 is also an angleiron extending from the troughs to the pipe; 400 are angle membersconnecting the side frames of the machine to the main frame of thescreen; 40I-40l are J-shaped members having the taller leg of the J ofconsiderable height; 402-402 are braces connecting the frame member 43with the lower portions of the J-shaped member; 403 is a brace directlyconnecting the two J-shaped members; 404 is a splash guard running thelength of the foraminous portion of the screen.

405-405 represent the support for the entire washing section; 406 is atank forming the base of the machine; 401 is one wall of the tank;408-408 are angle-shaped members forming channels with 401 and 4I6respectively running lengthwise of and within the wall 401 and 4l6; 408is the inclined bottom of the tank; 4l0 is a wall of the tank runninglengthwise of the apparatus and forming a weir which divides the tankinto two sections; 4Il is the bottom of the tank beyond the Weir; 4t2 isthe outer wall of the tank. in this case placed considerably beyond theouter wall of the screen section; 4I3 is the top of the said extendedside; 4I4 is a rectangular opening, channel-shaped in cross-section,forming a seat for cover 415. By lling the channel-shaped Amember partlywith water an effective gas-seal is created. 4|6 is a wall forming inpart the outer wall of the apparatus and in part a wall dividing the twocompartments of the tank; 4l1 are braces attached on the inside tochannels 408; 4|8 is a bar supported by braces 4l1; 4l9 are side platesextending lengthwise one on each side of the apparatus; 42| are sideplates attached to the braces 402-403 running lengthwise on each side ofthe apparatus and overlapping the upright portions of channel members408 inwardly thereof; 420 are drain guards attached to members 419 toprevent the drainage from the screen from running into' the channels408; 422 are drain guards attached to the walls of the screen chamberand projecting within the channels formed at the edges of the screen byangle members 49 and J-shaped members 40l-40I; 423-423 are walls of thescreen section of the apparatus; 424 is the top of the apparatus; 425 isa cover for an opening in the top of the apparatus, said cover beingformed with one continuous flange 426; 421 are continuous channels inthe top of the apparatus of size such that the continuous flange of thetop 425 may be seated in the channel which, being partly filled withliquid forms an effective hermetical seal. 428-428 are supports attachedto and projecting at right angles to the outer legs of the J-shapedmembers; 429-429 are wooden spring boards; 430 are beams to which thespring boards are bolted; 43l-43I are spring boards suspended from thebeams 430; 432 are weights hung from the said spring board; 433-433 areguides mounted on the frame 405 of the apparatus; 434-434 are buffermembers approaching the counterweights; 435 is a shaft journaled in theframe 405; 436 is a wheel capable of being driven by a belt or similarpower-transmitting means and, being keyed to the shaft 435, capable ofdriving the said shaft; 431-431 are eccentrics; 438-438 are driving rodsattached to the eccentrics 431 and attached through connections 439 tothe J-shaped screen frames; 440 are eccentrics placed on the shaftopposite to eccentrics 431 and on the outer sides of the frames 405respectively; 44l-44I are driving rods connecting the eccentrics to thecounterweights 432. The eccentrics, frame, and driving gear at thedischarge end of the machine are shown broken away to indicate that inpractice they are farther away from the tank than was permitted to beshown in the drawing.

442-442 are headers which may be suspended from the beams 430 byconnections 443 which comprise a band encircling the header having ahook to pierce an eye on a middle strip connected to the beams 430; 444are pipesA connected to the headers entering the washing tank throughhermetical seals 445; 446 are valves in the pipes 444;

l 441 are pressure gauges operatively connected to the pipes 444; 448are pipes connected horizontally to pipes 444; 449 are spray nozzlesaflixed to pipes 448 so that the liquid in pipes 448 may be directed atthe most eflicient angle upon the material on screen 450 are supportsattached to the tank at spaced intervals; are baille plates supported bysupports 450 extending transversely of the tank; 452 are channels at thebottom of the baffle to catch the drip and direct it to the sides of thescreen into the channels formed by angles 49 and sides 40| of the frame;453 are a series of supports extending transversely between walls 401-4i 6 of the machine and inclined with respect to the horizontal; 454 is aplate supported on supports 453, extending substantially the full lengthof the machine, inclined by the inclination of supports 453 andterminating short of wall y4|6; 455 are supports which also extendbetween the wall 4|6 and wall 401 and which have inclination opposite tothat of supports 458; 456 is a riilie plate substantially co-extensivewith the length of the machine and extending from the wall 4|6 to a lineshort of the wall 401.

In Figure l-a the screen is broken away at 454 to show the plain inclineplate 454; at 456 on the same gure the screen and plate 454 are brokenaway to show the rilile plate 456 and the diagonal placement of theriille bars. outlet at the bottom of the tank 406 and atthe juncture ofincline plate 409 and Weir 4|0; 458

is a pipe opening out of the portion of the tank j beyond the wier; 459is a blow-out pipe through which water under pressurecan be directed todischarge the sludge from the bottom of the tank through the orices 451;460 is a baiile plate at the end of the channel formed by members 49 and40|; 46| is a channel cut through members 49-49 so that any fluid insaid channel member maybe discharged uponlthe surface of and passthrough a iorarninous portion of the screen; 462 is al boot beneath thedischarge end 41 of the screen, separated from the tank as shown iii`Figure 4 and divided at vits center by partition 463 which prevents themingling of coal and slate.

In Figure l-e is shown the placement of the spray nozzles so that adouble overlap of spraying Water occurs. By this arrangement theplugging or failure of one spray will not affect the washing of the coalbecause the rtwo adjoining sprays will still overlap. v

The operation of the apparatus which has just been described, consideredin some detail, is as follows: Coal is discharged from the floatconveyor of the separator onto the receiving pan 4| .v and slate isdischarged from the sink y'conveyor i onto the receiving pan 42. 'I'helonger` leg of the J-shaped screen frames is, from the receiving to thedischarge end of the` screen, ofdecreasing 451 is ank coal and slatefrom mingling. .The driving mech-` anism reciprocates the screen at aratel which is consistent with the best performance andthe materials aremoved gradually from the receiving to the discharge end while beingvigorously sprayed by a multitude of showers. The motion o! the screeninl combination with the sprays turns the coal repeatedly over so thatall sides are-exposed to, and thoroughly washed with, the cleansingliquid, effectuating a substantially complete removal of the liquidwhich the material has carried with it. In order to prevent the stoppageof one shower from leaving the section of coal unwashed, the showers arearranged in overlapping series as shown in Figure 4-e so that eachparticle of coal is ordinarily sprayed by the water from three nozzles.

'I'he receiving pans 4|-42 of the screen are solid, thereafter thescreen becomes foraminous either by the punching ofA holes through theplate, by the use of ordinary screens, or by other means.

The nal section of the screen is made of wedge the material or thescreen. 'I'he direction of the sprays would build up air currentspassing from the receiving to the discharge end of the apparatus andconsiderable quantities of spray, containing recoverable liquid, wouldpass over the screen and down into the divided boot where it would belost and contaminate the coal. To prevent this, baiiie plates 45| areattached before each spray pipe so that the mist from the precedingspray will be caught upon the face of the' baflle, run down into channel45|, and be emptied into the channels formed by the members 49 and 40|of the screen from whence they will pass toward the dischargeend andv beissued through oriiices 46| upon the wedge-wirescreen. Substantially allliquids which are brought into the apparatus with the coal areI removedfrom the coal and passed through the screens. In addition there isremoved by the sprays a considerable quantity of ne solid particles,consisting mainly of earth and 4iinely divided lparticles of coal andslate, all belowla certain size passing through the screens with thewash liquid.

When the liquids with entrained solids pass through the screens, theyare prevented from reaching the sides of ythe tank by baffles 404,plates 4|9, 420, 42|, and 408. It will be observed that plates 4|9,which are rigid with the framel of the machine, have openings through4which pass the bars 403--402 of the screen, the openings in the wall ofplate 4|9 being of size to permit the reciprocating motion of thescreen. To prevent the discharge of liquid `through that opening intoythe seal the plates 42|, of a size adequate to cover the saidopenings'in all positions of the screen, are mounted on the rods 402-408and a baille plate 420 deflects'any vfluid flowing 'down the side ofplate 4|9 over and beyondthe said plate 42 I. All liquid ,which passesthrough the screen,v consequently, falls upon and j runsfdown theinclination of plate 454, ywhich is a plate having a surface whichpermits the maximum desirable transportation of the liquid. The plate454 is terminated short of the side wall and the liquids drop therefromat substantially the top of rife plate 456. I'hey run down the said rileplate, the solids tend to precipitate, and globules of heavy liquid tendto become larger globules so that. when the liquids have nally passedthe length of the riille plate, a partial separation of the constituentshas been effected. The rifile plate is terminated short of the side wall401 of the machine and the flow passes over the ends thereof and intothe tank 406, all of whose botton portions slope to the central lowpoint in the neighborhood of outlet 459. The sludge and some partingliquid settle in the vicinity ofv the opening 451 and the liquid whichcarries only comparatively fine particles of solidflows over the Weir410 into the other section of the tank, being pumped through orice 458to a recovery system, as is more fully elsewhere described. The sludgeis pumped through orice 451 to the recovery system, which is elsewheremore fully described. If the sludge has -collected so thickly at theorice 451 that the sludge pumps cannot draw it from the tank, a hose maybe attached to pipe 459 and water under pressure used to force the'sludge out of the chamber.

The screen is counterbalanced by the use of spring board supportedcounterweights driven by oppositely placed eccentrics from the sameshaft. The covers which give admittance to the tank are water sealed bythe use of flanged covers which fit water filled channel members in themachine casing.

In order to drive the screen, which is inside the tank, from the drivinggear, which is Outside, without permitting the escape of vapors, channelmembers partially filled with water are provided on4 each side of themachine. The screen frame is made J-shaped, each J projecting into theliquid within the said channels, and

being shorter than they by the length of the swing. The upper portion ofthe tank is then,

so to speak, placed within the hook of the J so that its lower edgeisbeneath the water level in the channel. The J-shaped frame,consequently, reciprocates within a water seal which effectivelyprevents the escape of gas, and the previously described construction ofthe apparatus prevents the contamination of the liquid in the saidchannels.

From the screen the coal and slate drop into divided boot 462. Givingadmittance to this boot are hermetically sealed covers 464. Hermeticallyattached to the boot on the one side is liquidtight conveyor box 51 andon the other side a similar conveyor box 52. The boot thus becomes twochutes, one for the coal and one for the slate. A description of one ofthese conveyors will suce for both. 51 is the conveyor box in general,being a gas and liquid-tight tank made of metal or other suitablematerial; 53 is a hopper within the said conveyor tank having an inclined wall 54 to direct the material which falls from the screen intothe conveyor box at the angle which offers the least interference withthe descending flights of the conveyor; 510 is the inclined underside ofthe conveyor tank; 511 is a displaced portion of the said side; 512 is aforaminous section forming a continuation of the portion of the bottom510, the portions 5H and 512 forming between them a space of a ca.-pacity adequate to take care of such liquid as may be discharged to themfrom the solids which are carried out of the tank by the flights. 505 isa conveyor pan; 506 are openings in the lower portion of the conveyorpan; 501 is a. section of wedge-wire screen forming the bottom of thesaid conveyor pan at a point just short of the discharge lip thereof; 58is the discharge lip of the conveyor pan over which the material ispushed by the conveyor; 59 is the supporting underlipof the conveyortank; 513 is a flight conveyor; 514 are sprocket wheels over which theconveyor chains are trained; 516 is a motor mounted on the frame 511 ofthe conveyor; 518-519-520-521-522-523 are a combined -power transmittingand speed reducing agency consisting, in the modification shown, of aseries of alternate large and small gears connected either Vdirectly orby means of iiexible driving means such as chains or ropes. 524 is awheel driven by means 523 and keyed to shaft 525 on which are keyed thesprocket wheels 514; 526 are bearings on the tank which support the rod525; 521 are parallel bearing blocks; 529 is a shaft journaled at oneend with a loose fit in the said bearing blocks 521 and at its other endin complementary bearing blocks, not shown, at the other side of theconveyor box. 530 is a rod fastened at one end to the shaft 529 andhaving at its upper end a screw-threaded nut 532; 531 is ascrew-threaded rod making operable screw-threaded contact with the nut532. One

of these rods is attached to each end of the shaft' 529. The rods 531are mounted on a rod which transverses and is attached to the sides ofthe tank. The conveyor may jump away from the pan due to the loose t ofthe blocks and may be manually adjusted by nuts 532. 541 is an openingin the base of the section 511 to which is attached a pipe, not shown,connected to the lower section of the conveyor whereby to return theliquid drained from the whole by the wedgewire screen to the conveyorbox at a lower point; 542 is an inlet pipe and valve through which4liquid can be run into conveyor box; 543 is an outlet pipe and valve atthe bottom of the conveyor which permit the drawing oif of such sludgeas may form there. The pipe 543 is connected either to a waste pit or tothe settling tank, which isv elsewhere herein more fully described. 544is a liquid box outside of the machine; 545 is an overflow pipe withinthe said liquid box.

'Ihe operation of the apparatus is as follows: Coal is dropped from thedischarge lip 48 of the screen through the divided boot and the hopper.The hopper and the conveyor tank are lled to the level 546 with wateror'other suitable liquid.

The coal is discharged into the water therefor above the hopper leveland is directed by the inclination of the chute 54 to a place inproximity to the descending nights of the night conveyor. The coalpasses through those flights and directly to the conveyor-pan wh'ere itis picked up by the ascending nights, drained of liquid by passage overthe wedge-wire screens and discharged over the discharge lip 58. Theliquid level in the apparatus is kept at the level 546 so that no fumesor liquids coming over the discharge end of the screen will be able toescape into the air. -The liquid which is drained through the wedge-wirescreen nils up the space between the conveyor pan and the tank andthereafter passes through the screen 512 into the space below from whichit is drained off by pipe 541 which returns it to 4the bottom of theconveyor lnk or elsewhere.

Means are provided, not shown in these drawings, for blowing out thespace between the conveyor pan and the bottom of the tank and consist ofa nozzle through which water can be forced under pressure at 459 as hashereinbefore been described for other apparatus.

The liquids which wash the coal in the washing section remove from thecoal and slate substantially all the heavy liquid and the iine particleswhich are produced by abrasion or which are carried through the machine.In the settling tank at the bottom of the washing apparatus the liquidwith ne suspensoidal matter is separated from the heavy sludge by theWeir.

'Ihe system vconsists essentially of three settling or Separating tanksinterconnected, of which the rst, located in the base of the washingsection, makes a preliminary division between sludge and liquidcontaining light suspensoidal matter, the second, called for purposes ofdifferentiation the main settling tank, separates the comparativelyvlight suspensoidal matter from the washing liquid and the third, calledfor convenience the sludge trap, receives the sludge from both the rstand second tanks.

Many modifications of the scrubbing process are possible. In addition tothe sprays herein shown, sprays may bejdirected from beneath the screento assist in the scrubbing of the coal. The concentrated table or riiiieboard can be omitted, but its omission is inadfvisable if preferredresults are to be obtained. It has been stated in the literature that nostatic means has been designed which is capable of separating coal sizefrom wash water. It is believed that the method of separation which isdisclosed representsthe rst successful separation of coal size andsolids by a semi-static process. In this separation the riiile plateplays a valuable. part by tending to precipitate the nes, coagulate theminute globules of parting liquid, and separate the water.

An advantage of this invention is the thorough removal from separatedsolids of adhering party ing liquid. Another advantageis an apparatusfor washing separated solids with agitation under ration is avoided.Another advantage of the invention is the suspension of a movable screenwithin a hermetically sealed compartment. Other advantages of theinvention, both that of the process and apparatus, will be apparent froma consideration of the specication and the claims. l

As many apparently widely different embodiments of this invention may bemade Without departing ,from the spirit and scope thereof, it is to beunderstood that We do not limit ourselves to the specific embodimentsthereof except as dened inthe appended claims.

We claim:

1. The process which comprises reciprocating and turning mineral matterbeneath Lconcentrated sprays of Water of high velocity, intercepting thesplash from the sprays and the air current set up thereby, removing theminerals from t'he'region of the sprays, and draining liquids therefrom.

2. Apparatus for the washing of solids which comprises an enclosure, areciprocable screen Within th'e enclosure, means to admit solids to thesurface of the screen, a Weir dividing the bottom of the enclosurebeneath the level of the screen, means to wash the solids on the surfaceof the screen, a riiiie boardbeneath the screen, means to direct thewashings which pass through .the screen to the upper side of the riiileboard, the said riiiie board delivering the rifiied washings to one sideof the said Weir, and means for withdrawing materials from both sides ofthe said weir.

3. Apparatus for the washing of minerals which comprises an enclosure,sprays within the enclosure, means beneath the sprays for reciprocatingand turning the minerals, means to conduct the minerals to the saidturning means, Weir means beneath rthe said turning means to divide thesaid enclosure, and means beneath the said turning means to agglomeratethe constituents of the liquids that drain therefrom, and to direct thesaid liquids and agglomerated constituents to one side of the said Weir.

4. An apparatus lhaving a hermetically sealed chamber with a wall, areciprocable element Within the chamber, an operating member and meansoutside the chamber to impart reciprocating motion thereto in adirection parallel to the Wall, the operating member being connected tothe reciprocable element, the wall having an opening at least as long asthe path of reciprocation, a portion of the reciprocable system passingthrough the -said opening in the Wall, a water cup surrounding theopening, and a plate having a skirt depending within the cup so that theopening can be sealed by filling the cup with liquid to level above thebottom of the skirt.

mman L. ALEXANDER.

G B. Forum.

